Water glossary

Anthropogenic processes - Anthropogenic effects, processes, objects, or materials are those that are derived from human activities, as opposed to those occurring in natural environments without human influences. The term is often used in the context of environmental externalities in the form of chemical or biological wastes that are produced as by-products of otherwise purposeful human activities. For instance, it is widely believed that the production of carbon dioxide is the primary factor driving anthropogenic climate change.

Aquaculture - Aquaculture is the cultivation of the natural produce of water (fish, shellfish, algae and other aquatic organisms). Also known as aquafarming, the term is distinguished from fishing by the idea of active human effort in maintaining or increasing the number of organisms involved, as opposed to simply taking them from the wild. Subsets of aquaculture include Mariculture (aquaculture in the ocean); Algaculture (the production of kelp/seaweed and other algae); Fish farming (the raising of catfish, tilapia and milkfish in freshwater And Brackish ponds or salmon in marine ponds); and the growing of cultured pearls.

Aquifer - 1/ A subsurface layer or layers of rock or other geological strata of sufficient porosity and permeability to allow either a significant flow of groundwater or the abstraction of significant quantities of groundwater. 2/ Layers of rock, sand or gravel that can absorb water and allow it to flow. An aquifer acts as a groundwater reservoir when the underlying rock is impermeable. This may be tapped by wells for domestic, agricultural or industrial use. A serious environmental problem arises when the aquifer is contaminated by the seepage of sewage or toxins from waste dumps. If the groundwater in coastal areas is over-used salt water can seep into the aquifer.

Atmospheric deposition - The transfer of substances in air to surfaces, including soil, vegetation, surface water, or indoor surfaces, by dry or wet processes. (S. L. Brown)

Biodiversity level - The term biodiversity describes the variety of life on our planet or a specific region, measurable as the variety within species, between species, and the variety of ecosystems.

Brackish water - Brackish water is water that is saltier than fresh water, but not as salty as seawater. It may result from mixing of seawater with fresh water, as in estuaries, but also certain human activities can produce brackish water, in particular certain civil engineering projects such as dikes and the flooding of coastal marshland. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment.

Catchment area - 1) An area from which surface runoff is carried away by a single drainage system. 2) The area of land bounded by watersheds draining into a river, basin or reservoir.

Diffuse pollution - Pollution from widespread activities with no one discrete source, e.g. acid rain, pesticides, urban run-off, etc.

Direct point source - A stationary location or fixed facility from which pollutants are discharged; any single identifiable source of pollution; e.g. a pipe, ditch, ship, ore pit, factory smokestack.

Downstream reaches - A reach is an expanse, or widening, of a stream or river channel. This commonly occurs after the river or stream is dammed.

Eutrophication - A process of pollution that occurs when a lake or stream becomes over-rich in plant nutrient; as a consequence it becomes overgrown in algae and other aquatic plants. The plants die and decompose. In decomposing the plants rob the water of oxygen and the lake, river or stream becomes lifeless. Nitrate fertilizers which drain from the fields, nutrients from animal wastes and human sewage are the primary causes of eutrophication.

Faecal microbes - Bacteria contained in human and animal faeces.

Groundwater abstraction - Groundwater abstraction is the process of taking water from a ground source, either temporarily or permanently. Most water is used for irrigation or treatment to produce drinking water. Depending on the environmental legislation in the relevant country, controls may be placed on abstraction to limit the amount of water that can be removed. Over abstraction can lead to rivers drying up or the level of groundwater aquifers reducing unacceptably. The science of hydrogeology is used to assess safe abstraction levels.

Hydrocarbons - Hydrocarbons are referred to as consisting of a "backbone" or "skeleton" composed entirely of carbon and hydrogen and other bonded compounds, and lack a functional group that generally facilitates combustion without adverse effects. The majority of hydrocarbons found naturally occur in crude oil, where decomposed organic matter provides an abundance of carbon and hydrogen which, when bonded can catenate to form seemingly limitless chains.

Hydrological cycle - The water cycle — technically known as the hydrological cycle — is the continuous circulation of water within the Earth's hydrosphere, and is driven by solar radiation. This includes the atmosphere, land, surface water and groundwater. As water moves through the cycle, it changes state between liquid, solid, and gas phases. Water moves from compartment to compartment, such as from river to ocean, by the physical processes of evaporation, precipitation, infiltration, runoff, and subsurface flow.

Impervious - Impervious surfaces seal the soil surface, eliminating rainwater infiltration and natural groundwater recharge.

Intrusion of saltwater - Saltwater intrusion is a natural process that occurs in virtually all coastal aquifers. It consists in salt water (from the sea) flowing inland in freshwater aquifers. This behavior is caused by the fact that sea water has a higher density (which is because it carries more solutes) than freshwater. This higher density has the effect that the pressure beneath a column of saltwater is larger than that beneath a column of the same height of freshwater. If these columns were connected at the bottom, then the pressure difference would trigger a flow from the saltwater column to the freshwater column.

Lake basin - A basin is a natural depression in the surface of the land. A lake basin is a geographic land area draining into a lake; also referred to as drainage basin or watershed.

Large basin management - A large basin is a natural or artificially created pond, lake or other space used for storage, regulation or control of water.

Microbial pathogens - Any disease-producing agent or microorganism.

Nutrients - Nutrients are chemical elements which are involved in the construction of living tissue and which are needed by both plant and animal. The most important in terms of bulk are carbon, hydrogen and oxygen, with other essential ones including nitrogen, potassium, calcium, sulphur and phosphorus.

Percolation - In chemistry and materials science, percolation concerns the movement and filtering of fluids through porous materials. During the last three decades, percolation theory, an extensive mathematical model of percolation, has brought new understanding and techniques to a broad range of topics in physics and materials science

Pollution - Pollution is the introduction of substances or energy into the environment, resulting in deleterious effects of such a nature as to endanger human health, harm living resources and ecosystems, and impair or interfere with amenities and other legitimate uses of the environment.

Precipitation - In meteorology, precipitation (also known as hydrometeor) is any product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It occurs when the atmosphere (being a large gaseous solution) becomes saturated with water vapors and the water condenses and falls out of solution (i.e., precipitates) Air becomes saturated via two processes, Cooling and Adding Moisture. Precipitation that reaches the surface of the earth can occur in many different forms, including rain, freezing rain, snow, sleet, and hail.

Recharge area - Aquifers are replenished with water from the surface through a process called "recharge." This occurs as a part of the hydrologic cycle when water from rainfall percolates into underlying aquifers. The rate of recharge can be influenced by different factors, such as soil, plant cover, water content of surface materials, and rainfall intensity. Groundwater recharge may also occur from surface water bodies in arid areas. Overwithdrawal of groundwater occurs when the discharge of groundwater in an aquifer exceeds the recharge rate over a period of time.

River basin - The area of land from which all surface run-off flows through a sequence of streams, rivers and, possibly, lakes into the sea at a single river mouth, estuary or delta.

Scattered dwellings - Scattered dwellings is a diffuse source sector used in the inventory of releases into water defined as discharge from households not connected to urban waste water treatment plants and other diffuse emissions as surface run-off from paved areas.

Suspended matter - Suspended matter is made up of fine particles. Some are present naturally in river water, such as plankton, fine plant debris and minerals, while others stem from human activity (organic and inorganic matter). Suspended matter can make water more turbid, which has a negative impact on river and stream biology.

Topography - The representation of a portion of the earth’s surface showing natural and man-made features of a given locality such as rivers, streams, ditches, lakes, roads, buildings and variations in ground elevations for the terrain of the area.

Toxins - A poisonous substance generally of plant or animal origin.

Tributaries - A tributary (or confluent/affluent) is a stream or river which flows into another river (a parent river) or body of water but which may not flow directly into the sea.

Turbid waters - Water is said to be turbid when particles suspended in it restrict the transmission of light and give a cloudy or muddy appearance. Only small particles can remain suspended for significant periods of time. Relatively large and dense particles such as sand grains will sink rapidly. All particles denser than water will tend to sink unless there is a force operating to keep them suspended. Normally some level of motion of the water assist in suspending particles. Thus the duration of suspension depends on the intensity of the motion plus the size shape and density of the particles. Soil particles and organic fragments are probably the most common materials suspended in farm water supplies.

Water body - Any mass of water having definite hydrological, physical, chemical and biological characteristics and which can be employed for one or several purposes.

Water pricing - Applying a monetary rate or value at which water can be bought or sold.

Water stress - Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use. Water stress causes deterioration of fresh water resources in terms of quantity (aquifer over-exploitation, dry rivers, etc.) and quality (eutrophication, organic matter pollution, saline intrusion, etc.).

Water table - The top of the water surface in the saturated part of an aquifer.

Watershed - The dividing line between two adjacent river systems, such as a ridge.